Power hinge actuators are devices utilized to actuate control surfaces on aircraft. To date, power hinge actuators derive their name from the way they are utilized; that is, they are mounted on the surface hinge line between a main aircraft structure and a rotatable control surface.
Mechanical rotary geared actuators receive power from electro-hydraulic power drive units via drive shafts. Hydraulic rotary vane actuators receive power from remote hydraulic servovalves. The disadvantage of locating power hinge actuators at the hinge line is that structural limitations do not permit adequate space to integrate the actuator with the associated power source. Further, a problem exists for wing control surface hinge actuators due to the fact that the wing structures are becoming thinner causing correspondingly thinner aerodynamic envelopes. Accordingly, if an actuator is to be mounted internally of the wing structure, there is a severely limited space available. Thus, the torque-generating capability of such actuators is severely limited. If larger linear actuators are to be mounted externally of the wing, they present a frontal area which extends beyond the aerodynamic envelope of the wing and, therefore, produce undesirable drag. Further, externally mounted actuators require connected control and power lines to be exposed which presents a potentially damaging situation.